Mest (Peg1, Paternally expressed gene 1, mesoderm-specific transcript) is paternally expressed (Kaneko-
T et al, 1995).
Loss of Peg1 imprinting occurred in a subset of F1 hybrids between M. musculus and M. spretus
W et al, 2004).
A maternally methylated germline DMR is located in the promoter of MEST (reported at
chr6:30686710-30687273, adjacent to CpG island at chr6:30687908-30688499 NCBI build 37; Lucifero
D et al, 2002).
Peg1/Mest expression (monoallelic) in upregulated in adipose tissue of obese mice (Kamei
Y et al, 2006).
A longer (>10 kb) transcript of Mest, called MestXL, extends into the downstream antisense gene
Copg2 . MestXL expression was tissue-specific, i.e., it was expressed in developing brain, but not
in heart and liver (MacIsaac J L et al, 2012). MestXL expression
controls the imprinting of Copg2 in tissues in which MestXL is expressed (see Copg2 entry). MestXL
was previously identified as Mit1/Lb9 (Lee
YJ et al, 2000)
Imprinted paternal expression of Mest was confirmed in placenta (Wang X et al, 2011 and Okae H et al, 2012 ) and in trophoblast
stem cells (Okae H et al, 2012).